#include <bits/stdc++.h>
using namespace std;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	double s, dis = 2, sum = 0;
	int ans = 0;
	cin >> s;
	while (sum < s)
	{
		++ans;
		sum += dis;
		dis *= 0.98;
	}
	cout << ans;
	return 0;
}
